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1.
It is shown how 1D nOe and 2D COSY 1H NMR spectroscopy can be used to assign the stereochemistry of Co(III) amine complexes. By using d6-DMSO as solvent together with a small quantity of DCl all non-equivalent N---H hydrogens can be distinguished at 300 MHz. Through-space (nOe), and through-bond (COSY), associations with other N---H and C---H hydrogens can then be determined. This leads to a complete assignment of structure in solution. The technique is applied to the complexes syn(N), anti(N)-[Co(cyclen) (NH3)2] (ClO4)3, syn(N), anti(Cl)-[Co(cyclen) (NH3)Cl] (ClO4)2, anti(N), syn(Cl)-[Co(cyclen) (NH3)Cl](ClO4)2, syn(N), anti(O)-[Co(Mecyclen)-(GlyO)](ClO4)2 and Δ-cis-[Co(δ-en)2(NO2)2](NO2).  相似文献   

2.
Cis(or trans)-[RuCl2(CO)2(PPh3)2] react with two and one equivalents of AgBF4 to give the recently reported [Ru(CO)2(PPh3)2][BF4]2·CH2Cl2 (1) and novel [RuCl(CO)2(PPh3)2][BF4] · 1/2 CH2Cl2 (2), respectively. Cis-[RuCl2(CO)2(PPh3)2] also reacts with two equivalents of AgBF4 in the presence of CO to give [Ru(CO)3(PPh3)2][BF4]2 (3). Reactions of 1 and 2 with NaOMe and CO at 1 atm produce the carbomethoxy species [Ru(COOMe)2(CO)2(PPh3)2] (4) and [RuCl(COOMe)(CO)2(PPh3)2] (5), respectively. Complex 4 can also be formed from the reaction of 3 with NaOMe and CO. Alternatively, 4 is formed from cis-[RuCl2(CO)2(PPh3)2] with NaOMe and CO at elevated pressure (10 atm); if these reactants are refluxed under 1 atm of CO, [Ru(CO)3(PPh3)2] is the product. The reaction of [RuCl(CO)3(PPh3)2][AlCl4] with NaOMe provides an alternative route to the preparation of 5, but the product is contaminated with [RuCl2(CO)2(PPh3)2]. Compounds 1. 2, 4 and 5 have been characterised by IR, 1H NMR and analysis, whilst the formulation of 3 is proposed from spectroscopic data only. This account also examines the reactivity of [Ru(CO)2(PPh3)2][BF4]2 · CH2Cl2 with NaBH4, conc. HCl, KI and, finally, MeCOONa in the presence of CO. The products of these reactions, namely cis-[RuH2(CO)2(PPh3)2], cis-[RuCl2(CO)2(PPh3)2], cis-[RuI2(CO)2(PPh3)2] and [Ru(OOCMe)2(CO)2(PPh3)2], have been identified by comparison of their spectra with previous literature.  相似文献   

3.
The dimetal μ-vinylidene complexes Cp(CO)2MnPt(μ-C = CHPh)L2 (L = tert.-phosphine or -phosphite), which have been obtained by coupling of the mononuclear complex Cp(CO)2Mn=C=CHPh and unsaturated PtL2 unit, add smoothly the Fe(CO)4 moiety to produce trimetal MnFePt compounds. The μ3-vinylidene cluster CpMnFePt(μ3-C=CHPh)(CO)6(PPh3) was prepared in quantitative yields from the reactions of Cp(CO)2MnPt(μ-C=CHPh)(PPh3)L (L = PPh3 or CO) with Fe2(CO)9 in benzene at 20 °C. The phosphite-substituted complexes Cp(CO)2Mnpt(μ-C=CHPh)L2 (L = P(OEt)3 or P(OPri)3) react under analogous conditions with Fe2(CO)9 to give mixtures (2:3) of the penta- and hexacarbonyl clusters, CpMnFePt(μ3-C = CHPh)(CO)5L2 and CpMnFePt(μ3-C = CHPh)(CO)6L, respectively. The similar reaction of the dimetal complex Cp(CO)2MnPt(μ-C = CHPh)(dppm), in which the Pt atom is chelated by dppm = Ph2PCH2PPhPin2 ligand, gives only a 15% yield of the analogous trimetal μ3-vinylidene hexacarbonyl product CpMnFePt(μ3-C = CHPh)(CO)(dppm), but the major product (40%) is the tetranuclear μ4-vinylidene cluster (dppm)PtFe3(μ4-C = CHPh)(CO)9. The IR and 1H, 13C and 31P NMR data for the new complexes are reported and discussed.  相似文献   

4.
The reaction of [N(PPh3)2]2[Ni6(CO)12] with Cu(PPh3)xCl (x=1, 2), as well as the degradation of [N(PPh3)2]2[H2Ni12(CO)21] with PPh3, affords the new and unstable dark orange–brown [N(PPh3)2]2[Ni9(CO)16].THF salt in low yields. This salt has been characterized by a CCD X-ray diffraction determination, along with IR spectroscopy and elemental analysis. The close-packed two-layer metal core geometry of the [Ni9(CO)16]2− dianion is directly related to that of the bimetallic [Ni6Rh3(CO)17]3− trianion and may be envisioned to be formally derived from the hcp three-layer geometry of [Ni12(CO)21]4− by the substitution of one of the two outer [Ni3(CO)3(μ−CO)3]2− layers with a face-bridging carbonyl group.  相似文献   

5.
Using thermal and photochemical methods a series of new chromium complexes has been prepared: (ν6-p-C6H4F2)Cr(CO)3; (ν6-C6H5CF3)Cr(CO)3; [m-C6H4(CF3)2]Cr(CO)3; (ν6-C6H5F)Cr(CO)2H(SiCl3); (ν6-C6H5F)Cr(CO)2(SiCl3)2; (p-C6H4F2)Cr(CO)2-H(SiCl3); (C6H5CF3)Cr(CO)2H(SiCl3(p-C6H4F2)Cr(CO)2(SiCl3)2; C6H5CF3)Cr(CO)2(SiCl3)2; [m-C6H4(CF3)2]Cr(CO)2-H(SiCl3); [m-C6H4(CF3)2]Cr(CO)2(SiCl3)2. Two compounds were structurally characterized by X-ray diffraction. These data combined with IR and 1H NMR have allowed assessment of some of the electronic and steric effects. The Cr-arene bond is considerably longer in the Cr(II) derivatives than in the Cr(0) species. Also the Cr center, as might be expected, is less electron rich in the Cr(II) dicarbonyl disilyl derivatives. The ν6-p-C6H4F2 ligands are slightly folded so that the C---F carbons are moved further away from the Cr center. Comparison of structural and electronic effects is made with a series of similar chromium compounds reported in the literature. These new (arene)Cr(II) derivatives possess more labile ν6-arene ligands, which promise a rich chemistry at the chromium center.  相似文献   

6.
The complexes RuC(CCPh)=CPhC(CCPh)=CPh(CO)3(NMe3) (3), Ru2μ-C(CCPh)=CPhC(CCPh)=CPh(CO)6 (1), Ru2μ-[C(CCPh)=CPh]2CO(CO)6 (2), Ru3(μ3-PhC2CCPh)(μ-CO)(CO)9 (4) and Ru4(μ4-PhC2CCPh)(CO)12 (5) have been isolated from reactions between PhC2C2Ph and Ru3(CO)12 or RU3(CO)10(NCMe)2. The molecular structures of complexes 1, 2, 3 and 5 have been determined from single-crystal X-ray studies. All complexes have precedents in similar products obtained from reactions involving mono-ynes; in the present cases, each alkyne fragment retains a phenylethynyl (PhCC---) group as a non-coordinated substituent.  相似文献   

7.
Reactions of cct-RuH(SR)(CO)2(PPh3)2 (1) (cct = cis, cis, trans) with R′SH provide cct-RuH(SR′)(CO)2(PPh3)2 (R = alkyl, aryl): based on described kinetic data, the proposed mechanism involves PPh3 loss, coordination of R′SH, intramolecular protonation of RS− by R′SH, and RSH elimination. The intramolecular protonation step circumvents a potentially slow RSH reductive elimination step. A similar mechanism is proposed for the thiol exchange reactions of cct-Ru(SR)2(CO)2(PPh3)2 (2). A corresponding dissociative mechanism is also proposed for the reaction of 1 with P(p-tolyl)3, which gives cct-RuH(SR)(CO)2(PPh3)(P(p-tolyl)3) and cct-RuH(SR)(CO)2− (P(p-tolyl)3)2. Other reactions described include the reactions of 1 with H2, CO, HCl and PPh3, and the reactions of 2 with P(p-tolyl)3 and H2. Exposure to light causes 2 to dimerize in solution.  相似文献   

8.
Analogy with the isolable oxo cluster [Fe3(CO)9(μ3-O)]2−, which is structurally interesting and synthetically useful, prompted the present attempt to synthesize its ruthenium analog. Although the high reactivity of [Ru3(CO)9(μ3-O)]2− (I) prevented its isolation, the reaction of this species with [M(CO)3(NCCH3)]+, where M = Mn or Re, yields [PPN][MRu3(CO)12(η2-μ3-NC(μ-O)CH3]−. The high nucleophilicity of the oxo ligand in [Ru3(CO)9(μ3-O)]2− (I) appears to be responsible for the conversion of acetonitrile to an acetamidediato ligand and for the instability of I. The crystal structure of [PPN][MnRu3(CO)12(η2-μ3-NC(μ-O)CH3)]] reveals a hinged butterfly array of metal atoms in which the acetamidediato ligand bridges the two wings with μ3-N bonding to an Mn and two Ru atoms, and μ-O bonding to an Ru atom.  相似文献   

9.
Protonation of Na3[Ta(CO)5] in liquid ammonia provides the thermally unstable Na[Ta(CO)5NH3], which may be isolated as the crystalline and deep violet salt [Ph4As][Ta(CO)5NH3]. Sodium amminepentacarbonyltantalate(1−) reacts with PMe3, PPh3, P(OMe)3, AsPh3, SbPh3, CNtBu and CN− at about 0°C in NH3/THF to give exclusively the corresponding [Ta(CO)5L]z. These have been isolated as tetraethylammonium salts in 54–84% yields.  相似文献   

10.
Rhodium complexes, in the presence or absence of PEt3, catalyse the carbonylation of CH2I2 to dialkylmalonates in the presence of alcohols (ROH, R=Me, Et, Pr1, Bu) with side products from reactions in EtOH being CH2(OEt)2, EtI and traces of EtCO2Et and EtOAc. The active species when using PEt3 is shown to be [RhI(CO)(PEt3)2], formed via [Rh(OAc)(CO)(PEt3)2] from [Rh2(OAc)4 · 2MeOH] and PEt3. Mechanistic studies show that the first step of the catalytic cycle is oxidative addition of CH2I2 to give [Rh(CH2I)I2(CO)(PEt3)2], but that insertion of CO into the Rh---CH2I bond gives an iodoacyl complex which is unstable. The analogous [Rh(COCH2X)X2(CO)(PEt3)2], (X=Cl or Br) have been synthesised by oxidative addition of XCH2COX to [RhX(CO)(PEt3)2] and fully characterised (by X-ray crystallography, for X=Cl). [Rh(COCH2Br)Br2(CO)(PEt3)2] has also been formed from reaction of [Rh(COCH2Cl)Cl2(CO)(PEt3)2] with excess NaBr. However, the analogous reaction with NaI does not give the iodoethanoyl complex, but rather [RhI3(CO)(PEt3)2] and its decomposition products. It is proposed that [Rh(COCH2I)I2(CO)(PEt3)2] is unstable towards loss of I− to form the ketene complex, [RhI2(CH2=C=O)(CO)(PEt3)2]I, which is transformed into [Rh(COCH2CO2Et)I2(CO)(PEt3)] by nucleophilic attack of ethanol at the central C atom, followed by CO insertion into the Rh---C bond. An analogue, [Rh(COCH2CO2Et)Cl2(CO)(PEt3)2], has been isolated by oxidative addition of EtO2CCH2COCl across [RhCl(CO)(PEt3)2], and characterised both spectroscopically and crystallographically. In refluxing ethanol, [Rh(COCH2CO2Et)Cl2(CO)(PEt3)2] produces diethylmalonate and [RhCl(CO)(PEt3)2], thus completing the catalytic cycle. Possible pathways of deactivation of the catalyst to give [RhI3(CO)(PEt3)2] are discussed. One involves the reaction of ketene with ethanol to give EtOAc, whilst the others involve protonation of the Rh---Z bond in [RhZI2(CO)(PEt3)2] (where Z =CH2I, CH2CO2Et or H) by HI. The isolation of CH2DCO2Et, when carrying out the reaction in EtOD, is consistent with all of these deactivation pathways except protonation of [RhHI2(CO)(PEt3)2].  相似文献   

11.
The complex [Et4N][W(CO)5OMe] (1) has been prepared from the reaction of the photochemically generated W(CO)5THF adduct and [Et4N][OH] in methanol. Complex 1 was shown to undergo rapid CO dissociation in THF to quantitatively provide the dimeric dianion, [W(CO)4OMe]22−. The resulting THF insoluble salt [Et4N]2[W(CO)4OMe]2 (2) has been structurally characterized by X-ray crystallography, with the doubly bridging methoxide ligands being in an anti configuration. Complex 2 was found to subsequently react with excess methoxide ligand in a THF slurry to afford the face-sharing octahedron complex [Et4N]3[W2(CO)6(OMe)3] (3) which contains three doubly bridging methoxide groups. In the absence of excess methoxide ligand complex 2 cleanly yields the tetrameric complex [Et4N]4[W(CO)3OMe]4 (4) which has been structurally characterized as a cubane-like arrangement with triply bridging μ3-methoxide groups and W(CO)3 units. Although complex 3 was not characterized in the solid state, the closely related glycolate derivative [Et4N]3[W2(CO)6(OCH2CH2OH)3] (5) was synthesized and its structure determined by X-ray crystallography. The trianions of complex 5 are linked in the crystal lattice by strong intermolecular hydrogen bonds. Crystal data for 2: space group P21/n, a = 7.696(2), b = 22.019(4), c = 9.714(2) Å, β = 92.22(3)°, Z = 4, R = 6.43%. Crystal data for 4: space group Fddd, a = 12.433(9), b = 24.01(2), c = 39.29(3) Å, Z = 8, R = 8.13%. Crystal data for 5: space group P212121, a = 11.43(2), b = 12.91(1), c = 29.85(6) Å, Z = 8, R = 8.29%. Finally, the rate of CO ligand dissociation in the closely related aryloxide derivatives [Et4N][W(CO)5OR] (R = C6H5 and 3,5-F2C6H3) were measured to be 2.15 × 10−2 and 1.31 × 10−3 s−1, respectively, in THF solution at 5°C. Hence, the value of the rate constant of 2.15 × 10−2 s−1 establishes a lower limit for the first-order rate constant for CO loss in the W(CO)5OMe− anion, since the methoxide ligand is a better π-donating group than phenoxide.  相似文献   

12.
UV photolysis of Ru3(CO)12 physisorbed onto porous Vycor glass leads to the oxidative addition product (μ-H)Ru3(CO)10(μ-OSi). The latter reacts thermally with 1-pentene to form a stable adduct, HRu3(CO)10(OSi)(1-C5H10), and photolysis of the adduct results in isomerization of the alkene. HRu3(CO)10(OSi)(1-C5H10) + hv → (μ-H)Ru3(CO)10(μ-OSi) + 2-pentene As with other photoactivated hybrid systems, the cis-/trans-2-pentene product ratio changes during photolysis. Unlike the other systems, where light generates a thermal catalyst, the data gathered here indicate a photoassisted catalytic process in which photoactivation of HRu3(CO)10(OSi)(1-C5H10) leads to an excited state similar to a π-allyl complex.  相似文献   

13.
The enthalpies of reaction of HMo(CO)3C5R5 (R = H, CH3) with diphenyldisulfide producing PhSMo(CO)3C5R5 and PhSH have been measured in toluene and THF solution (R = H, ΔH= −8.5 ± 0.5 kcal mol−1 (tol), −10.8 ± 0.7 kcal mol−1 (THF); R = CH3, ΔH = −11.3±0.3 kcal mol−1 (tol), −13.2±0.7 kcal mol−1 (THF)). These data are used to estimate the Mo---SPh bond strength to be on the order of 38–41 kcal mol−1 for these complexes. The increased exothermicity of oxidative addition of disulfide in THF versus toluene is attributed to hydrogen bonding between thiophenol produced in the reaction and THF. This was confirmed by measurement of the heat of solution of thiophenol in toluene and THF. Differential scanning calorimetry as well as high temperature calorimetry have been performed on the dimerization and subsequent decarbonylation reactions of PhSMo(CO)3Cp yielding [PhSMo(CO)2Cp]2 and [PhSMo(CO)Cp]2. The enthalpies of reaction of PhSMo(CO)3Cp and [PhSMo(CO)2Cp]2 with PPh3, PPh2Me and P(OMe)3 have also been measured. The disproportionation reaction: 2[PhSMo(CO)2Cp]2 → 2PhSMo(CO)3Cp + [PhSMP(CO)Cp]2 is reported and its enthalpy has also been measured. These data allow determination of the enthalpy of formation of the metal-sulfur clusters [PhSMo(CO)nC5H5]2, N = 1,2.  相似文献   

14.
The complex Ir(CH3) (CO) (CF3SO3)2 (dppe) (1) has been synthesized from the reaction of Ir(CH3)I2(CO) (dppe) and silver triflate. Methane and IrH(CO) (CF3SO3)2 (dppe) (2) are formed when a methylene chloride solution of 1 is placed under 760 torr dihydrogen. Conductivity studies indicate that methylene chloride solutions of complexes 1 and 2 are weak electrolytes and only partially ionized at concentrations above 1 mM. Complex 2 is an effective hydrogenation catalyst for ethylene and 1-hexene while acetone hydrogenation is inhibited by the formation of [IrH2(HOCH(CH3)2) (CO) (dppe)] (OTf) (3). Linear dimerization and polymerization of styrene occurs via a carbocationic mechanism initiated by triflic acid elimination from 2. Treatment of an acetonitrile solution of Ir(CH3)I2(CO) (dppe) with silver hexafluorophosphate produces the solvent promoted carbonyl insertion product [Ir(C(O)CH3) (NCCH3)3 (dppe)] [PF6]2 (7) which readily undergoes deinsertion in methylene chloride to form [Ir(CH3) (CO) (NCCH3)2 (dppe)] [PF6]2 (8) and acetonitrile.  相似文献   

15.
The kinetics in heptane of displacement of the alkene ligands ethene and methyl acrylate from Ru(CO)4(η2-alkene) by P(OEt)3 have been measured. The reactions occur by reversible dissociation of the alkenes, and activation parameters are compared with those for dissociation of CO from Ru(CO)5 and for reactions of the corresponding Os complexes. A linear free energy relationship for ligand dissociation from Ru(CO)5, Ru(CO)4(C2H4) and Ru(CO)4(MA) has a gradient close to unity, indicating virtually complete bond breaking in the transition states. Competition parameters for reactions of what is probably a solvated Ru(CO)4S intermediate have been measured for the alkenes and P(OEt)3, and for eleven other P-donor nucleophiles. Correlations with the electronic and steric properties of the P-donors show negligible dependence on the electron donicity of the nucleophiles and a small but significant dependence on their sizes. The sizes were quantified by Tolman cone angles or by ‘cone angle equivalents’ derived directly from Brown's ligand repulsion energies (Er). These correlations compared with those, reported elsewhere, for reactions of the probably solvated intermediates Co2(CO)5(μ2-C2Ph2) and H3Re3(CO)11 formed by ligand dissociative processes. In all cases the discrimination between nucleophiles by the intermediates is weak confirming their high reactivity and the borderline nature of the mechanisms of these bimolecular reactions between Id and Ia.  相似文献   

16.
Possible mechanisms for the silylformylation of 1-alkynes catalyzed by Rh2Co2(CO)12 are investigated. Novel Rh-Co mixed metal complexes, (PhMe2Si)2Rh(CO)nCo(CO)4 (n = 2 or 3) (3) and RhCo(HC≡CBun)(CO)5 (5), are found to play important roles in this catalysis. The reaction of 3 with 1-hexyne and HSiMe2Ph at ambient temperature and pressure of CO gives n-BuC(CHO)=CHSiMe2Ph (1a, Z/E = 95/5), (PhMe2Si)2Rh(CO)3Co(CO)4 (3-B) and an Rh-Co mixed metal butterfly complex, h2Co2(HC≡CBun)(CO)10 (4). The reaction of 5 with 1-hexyne and HSiMe2Ph under the same ambient conditions affords 1a (100% Z) very cleanly as the sole reaction product. The crossover experiments u sing RhCo(DC≡CBun)(CO)5(5-d), 1-hexyne-1d and DSiMe2Ph strongly support the mixed metal bimetallic catalysis and involvement of bis(alkyne)-Rh-Co species. The most plausible catalytic cycle of silylformylation which can accommodate all the observed results is proposed.  相似文献   

17.
A series of tetrakis(trimethylsilylethyne) derivatives of Group 14 metals (2–4) was prepared. Co2(CO)6 complexes 5–10 were synthesised by the reaction of 2–4 with Co2(CO)8. From the silyl and germyl based compounds 2 and 3, either one or two alkynes could be complexed with Co2(CO)6. In contrast, the tin derived compound 4 could accommodate up to four Co2(CO)6 complexes. The longest wavelength UV-Vis absorbances of the silicon and germanium-based complexes were consistent with multiple, non-conjugated Co2(CO)6 chromophores. The tetrakis Co2(CO)6 complex 10, however, absorbs at a much longer wavelength suggesting conjugation of Co2(CO)6 complexes through the tin. The reactivity towards protonolysis of the uncomplexed alkynes 2–4 is a consequence of the hyperconjugative stabilisation of the intermediate β-vinyl cation (the β-effect): Sn(CCSiMe3)3>SnOTf(CCSiMe3)2>SiMe3>Ge(CCSiMe3)3. The reactivity of the Co2(CO)6 complexes, however, was quite different from the reactions of 2–4 and from analogous all-carbon systems. Treatment of 5–10 with strong acid led neither to protiodemetallation of the complexed or non-complexed alkynes but to decomplexation of the cobalt. Similarly, ligand metathesis reactions between 10 and Ph2SiCl2 were not observed. The normal reactivity of silylalkynes towards electrophiles, which was expected to be enhanced by the presence of the cobalt complex, was diminished by the particular steric environment of the molecules under examination (5–10). As a result, the favoured reaction under these conditions was decomplexation of the cobalt.  相似文献   

18.
Kinetic and activation parameter data for the reactions of cct-Ru(H)2(CO)2(PPh3)2 (1) (cct = cis, cis, trans) in THF with thiols, CO and PPh3 to give cct-RuH(SR)(CO)2(PPh3)2, Ru(CO)3(PPh3)2 and Ru(CO)2(PPh3)2, respectively, reveal a common, rate-determining step, the initial dissociation of H2 from 1; the activated complex probably resembles the corresponding Ru(η2-H2) species. Reaction of Ru(H)2(dppm)2 (2) (as a cis/trans mixture, DPPM = bis(diphenylphosphino)methane) with thiols initially generated cis- and trans- RuH(SR) (dppm)2 with a rate that depends on both the type and concentration of thiol. The higher basicity of the hydride ligands in 2 (versus 1), which is demonstrated by deuterium exchange with CD3OD, gives rise in the thiol reaction to an initial protonation step prior to loss of H2. A species detected in the thiol reaction is possibly [RuH(η2-H2 (dppm)2]2, the anticipated intermediate for this reaction and for the hydrogen exchange with alcohol. A longer reaction of 2 with PhCH2SH gives solely cis-Ru(SCH2Ph)2(dppm)2.  相似文献   

19.
Reactions of [Rh(COD)Cl]2 with the ligand RN(PX2)2 (1: R = C6H5; X = OC6H5) give mono- or disubstituted complexes of the type [Rh2(COD)Cl2{ν2−C6H5N(P(OC6H5)2)2}] or [RhCl{ν2−C6H5 N(P(OC6H5)2)2 }]2 depending on the reaction conditions. Reaction of 1 with [Rh(CO)2Cl]2 gives the symmetric binuclear complex, [Rh(CO)Cl{μ−C6H5N(P(OC6H5)2)2} 2, whereas the same reaction with 2 (R = CH3; X = OC6H5) leads to the formation of an asymmetric complex of the type [Rh(CO)(μ−CO)Cl{μ−CH3N(P(OC6H5)2)2}2 containing both terminal and bridging CO groups. Interestingly the reaction of 3 (R = C6H5, X = OC6H4Br−p with either [Rh(COD)Cl]2 or [Rh(CO)2Cl]2 leads only to the formation of the chlorine bridged binuclear complex, [RhCl{ν2−C6H5N(P(OC6H4Br−p)2)2}]2. The structural elucidation of the complexes was carried out by elemental analyses, IR and 31P NMR spectroscopic data.  相似文献   

20.
A new synthetic process is reported for the preparation of two substituted metal carbonyls, (p-CH3OC6H4)2TeM(CO)5 (M = Mo, W). In the presence of (p-CH3OC6H4)2TeO as O atom transfer reagent in tetrahydrofuran solvent, a CO ligand is replaced by telluroether when M(CO)6 (M = Mo, W) is reacted with (p-CH3OC6H4)2TeO under very mild experimental conditions (r.t.). The products were characterized by elemental analysis, mass, IR and 1H NMR spectroscopies. The spectra suggest that the coordination geometry is distorted from a regular octahedral structure due to an asymmetrical bulky telluroether ligand on the metal atom. Kinetics of these reactions of M(CO)6 with (p-CH3OC6H4)2TeO show the reactions are first order in the concentration of M(CO)6 and of Te oxide. The rates of reaction decrease in the order W(CO)6>Mo(CO)6>Cr(CO)6, and the results obtained are discussed in term of a presumed mechanism.  相似文献   

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